The creation and utilization of a disk file involve various decisions to be made, such as an appropriate naming for the file, data type to be used, purpose of creating the file and method used in the creation of file.A Filename refers to a unique string of characters that facilitates easy identification of files on the disk.
Random Access File means that the data can be read from or written to random location in a file. In the File class, data is read from and written sequentially as continuous streams of data. The java.io package comprises a class known as RandomAccessFile that allows performing input/ output operations to any location within a file.
Applets are simple Java programs that runs in web browsers.The creation of web pages is related to Java Applet. An applet is an Internet based Java program that can be included in an HTML page.An applet is a Java class defined in JDK’s java. applet package.
The strlen() function, find the length of a string. This fuction counts the number of characters presents in a string. String.h has to be included in the program before you call the strlen().
A string constant is a series of characters(array of characters or group of characters) enclosed with double quotes(like “GOOD “).A string constant is a one dimensional(str11) array of characters. A character constant is a character enclosed in single quotes.(like ‘G ‘). Each character in a string takes only 1 byte.
Table is the Combination of rows and columns. With the help of Table we can display the data. A software application with a colorless screen interface would be dull and lifeless. Adding colour to it more attractive and captivating. The java.awt.Color class is used to add color to the applications and applets.
JButton Group component is used to manage the Buttons. By using JButtonGroup we can select only one option at a time.Controls are components like Buttons, textboxes that can be added to container like frames,panels etc.
The JTable class is a component of Swing programming which presents the user data within a scrolltable.Changing the name of the Column in JTable we use the method ChangeName().
By using Graphics we can draw the geometric figures like circle, line, ellipse, bar etc.
In this we set the coordinates like leftt,top,right,bottomm.Graphics.h library is used for graphics (initgraph method).
As frame, panels, and applets are Swing components, similarly labels are also Swing components. The idea behind using JLabel is to display an area for a short text string or an image, or both. Labels do not respond to input events;hence, JLabel does not receive the keyboard focus. The label can be aligned by setting the label’s contents using the vertical and horizontal alignment.